The recent rapid dissemination of smartphones and other mobile and wearable electronic terminals reflect the demand for faster, thinner and smaller products which are more compact and power-efficient. To meet these requirements, the size of various components in semiconductor packages such as fiber optic receivers, transmitters, transceivers, and transponders continue to shrink. As a result, the small area and close proximity of integrated circuits (ICs) in these modules demands small semiconductor packages with excellent thermal properties to dissipate heat generated by the semiconductor chip inside the package. With high frequency devices, small size is not only convenient but it is also a necessity of the design.
Conventional methods for transferring heat away from the semiconductor chip in semiconductor packages typically rely on providing a thermally conductive package substrate (e.g., metal lead frame, ceramic substrate) as a primary heat sink element. However, the die attach layer used for mounting a semiconductor chip to a thermally conductive package substrate are conventionally formed from heat insulating adhesive materials (e.g., polyimide tape) which impedes the thermal conductance between the semiconductor chip and package substrate. In addition, conventional solutions for improving heat dissipation properties of lead frame-based semiconductor packages include increasing a thickness of the lead frame up to about 20 mils. However, increasing a thickness of the lead frame leads to several disadvantages. For example, a thicker lead frame undesirably increases the pitch between lead fingers and increases the wear rate of a saw blade used for singulating the lead frame to form individual semiconductor packages. In another example, employing thicker lead frames invariably increases the difficulty in bending lead fingers into desired configurations.
From the foregoing discussion, there is a desire to provide a semiconductor package having improved heat dissipation performance without increasing package substrate thickness. It is also desirable to provide a cost-efficient method of producing such a semiconductor package.